The present invention relates to improvements in the fastening of heat sinks and associated electronic components with printed circuit boards, and, in one particular aspect, to unique and advantageous composite stamped-metal heat sinks soundly integrated with staked-on flat sheet-metal tabs to which solder will adhere readily and which are disposed to project through printed-circuit-board openings for convenient soldered locking in place when wave-soldering is performed.
Electronic semiconductor devices and circuit modules have power-handling limitations which are largely determined by their abilities to expel and avoid build-up of internally-generated heat. Such capabilities can be significantly extended and enlarged with the aid of finned metal extrusions or stampings which will conduct and radiate heat away from thermally-vulnerable regions, thereby upgrading low-cost devices into more demanding service than their uncooled ratings would otherwise allow. In most modern applications, the heat sinks cooperate with devices or modules disposed on or as part of printed circuitry, wherein a relatively sturdy insulating "board" serves as a mounting base and has networks of conductive foil-like connection paths on its surfaces. Preferably, the heat sinks required in such applications should be adaptable to inexpensive and labor-saving installation on the boards, and should be reliably connectable mechanically and electrically with the board and its conductors.
It has been a well-known practice to spring-clip miniature heat sinks onto small semiconductor devices (U.S. Pat. Nos. 3,572,428 and 4,012,769) and such devices have been soldered into place, via their electrical leads, on printed circuit boards, with their heat sinks clipped on top (U.S. Pat. No. 3,247,896). Further, a tab from such a heat sink has been utilized to make a separate soldered connection with the board, and to promote thermal and electrical contacting (U.S. Pat. No. 3,222,580). It has also been known to utilize solderable threaded studs and spacers which will allow for wave-soldered connections of heat sinks to printed circuit boards, as described in my copending joint U.S. Pat. No. 4,321,423, with Philip A. Johnson, for "Heat Sink Fastenings" Heat sinks with mounting tabs are also depicted in U.S. Pat. Nos. Des. 260,388 and Des. 260,761.